1. Field of the Invention
This invention relates to conveying apparatus, and more particularly to conveying apparatus for conveying flat articles having two locating holes each, the apparatus including spaced pairs of upstanding stacking pins to receive and convey a plurality of groups of the flat articles.
2. Desscription of the Prior Art
Apparatus for making flat bags of paper or plastic film usually includes a so-called wicketer feeder, which is downstream of a bag forming station and upstream of a bag conveyor. The bag forming station includes a transverse welding apparatus for severing plastic bags or the like from a tubular or semitubular plastic film web and for welding panel of the bags. Each of the plastic bags is provided with two spaced locating hole along and adjacent to an edge of the bag, and the bags are received from the bag forming station and are deposited on the radial arms of the rotatable wicketer, which carries the bags through about 180 degrees of wicketer rotation to transfer the bags from the bag forming station to a conveyor that include stacking pins that are spaced to receive the bags. The wicketer transfers the bags so that the stacking pins extend through the locating holes in the bags. Each adjacent pair of stacking pins receives a number of bag to define a stack. When a stack of a predetermined number of bags has been formed, the conveyor is incrementally advanced to move another pair of stacking pins to a stacking position to receive bags from the wicketer.
It is often desired to stack and convey bags which differ in size, or in which the locating holes have different spacings, and therefore adjustability of the spacing of the pairs of stacking pins is desirable. Bag conveying apparatus that permits adjustment of stacking pin spacing is disclosed in U.S. Pat. No. 4,252,233, and includes a pair of adjacent, parallel endless chains having links that are connected to carrying plates which each carry stacking pin. The position of each conveying plate is adjustable along the chains and is provided on its underside with a base plate having a side face that protrudes from a carrying plate. The base plate is provided on its top with two pins, which are guided in a longitudinal groove of a clamping rail. The clamping rail bears on the base plate and is adapted to be forced against the carrying plate by means of screws. When the clamping rail has been released, the stacking pins of each pair can be adjusted to the desired spacing. For this purpose, adjusting arms are pivotally mounted laterally of and above the stacking conveyor and adapted to receive at their free ends the tips of the stacking pins and are pivotally movable to adjust the stacking pins. When the stacking pins have been adjusted to the desired spacing, the clamping rails can be tightened. However, the adjustement of the pairs of stacking pins is a complicated and time-consuming operation because the stacking pins of each pair must be released, adjusted to the desire spacing by means of the adjusting arms, and then secure in position before the stacking pins of the next pair can be moved to a position adjacent to the adjusting arms.
It is an object of the present invention to provide conveying apparatus having stacking pins and in which the spacing of the stacking pins of each pair can be adjusted more easily and more quickly to accommodate bags of a different size, or bags having different locating hole spacings.